From: Charles Comstock <cc1@...>
Date: 2004-07-07T17:17:36+09:00
Subject: Re: Class#=== has interesting results

> 
> whatisit = case obj
> 	   when Array
> 	      "it's an array!"
> 	   when Hash
> 	      "it's a hash!"
> 	   when Septuagenarian
> 	      "it's a septuagenarian!"
> 	   end
> 
> $ ri Module#===
> ------------------------------------------------------------- Module#===
>      mod === obj    => true or false
> ------------------------------------------------------------------------
>      Case Equality---Returns +true+ if _anObject_ is an instance of
>      _mod_ or one of _mod_'s descendents. Of limited use for modules,
>      but can be used in +case+ statements to classify objects by class.
> 

Right I was trying to use it in an example almost exactly like that 
except that obj was a name of a commandclass.

Ie:
   def parse(str)
     input = str.chomp.split
     comm = CommandFactory[input[0]]

     case comm
     when StartCommand
       comm.new(input[1],input[2..-1])
       @mobile = input[1]
     when HelpCommand
     else
       comm.new(@mobile,input[1..-1])
     end
   end

The idea was for a command factory to return the name of the command, 
and instantiate that command with the rest of the string as parameters, 
except for a few special case examples which would be checked against in 
a case statement.  Since StartCommand === StartCommand returns false 
this doesn't work.  Why you would want == to return true and === to 
return false in this case is beyond me.  I knew about the example you 
gave above, that was what I was trying to emulate except at a step before.

Charles Comstock